The present invention relates to the field of medical devices. This device is intended to be selectively implanted beneath the skin of the patient and provides a mechanism which will allow for drainage of a body cavity or, alternatively, the introduction of medication into a body cavity. For example, a patient having fluid in their chest that keeps recurring can have the device of the present invention implanted under the skin, over the ribs and the open end of the stem can be located in the pleural cavity. The same device can be used in the abdomen sot that if fluid collects, for example, in the peritoneal cavity, the cap of the device can be beneath the skin and the open end of the stem below the peritoneum.
Preferably, however, the device can be implanted into a human patient below the skin of the head but above the hard skull for draining the subdural cavity and/or providing medication thereto. For ease of illustration and reading, and in that the present invention has its preferred embodiment for use in connection with the subdural cavity, the present invention will be described for that purpose, it being understood by those reading the same that the invention is not so limited but, rather, will extend in scope to other human drainage usages and/or provision of medication to a human, beneath the skin and into a cavity. The scope of the invention is intended to extend to the fullest extent of the scope of the appended claims as worded and as interpreted by the Courts.
In the preferred embodiment, then, a subdural drain is provided which has one portion above the skull and below the skin while the other portion of the device extends through the skull and into the subdural space. That space is generally considered to be the area or volume which is between the inside of the hard skull and the brain. The present invention is a subdural drain which is intended to allow for selective removal of fluid from the subdural space or the introduction therein of medication, all under a physician's care and guidance. The device can be left in situ for extended periods of time and thus allows the physician to properly treat his or her patient by either allowing for selective drainage (either by use of a hypodermic syringe sucking out fluid, the syringe passing through the cap of the device or by a drainage bag being secured to the tube extending through the device and into the subdural space) or for selective providing of medication (again, by use of a loaded-with-medication syringe directed into either the tube and/or the cap of the device which allows the medication to flow into the subdural space). If and when deemed necessary, the device can be removed from the skull and discarded and then the skull plugged and the skin thereover sutured or otherwise secured back.
The present invention is a basic mushroom-shaped, preferably silastic drain for placement under the skin with the cap of the mushroom shape beneath the skin of the skull and brain but above the skull and the stem of the mushroom shape passing through the skull and into the subdural space for selectively draining of fluid or providing medication from and to the subdural space. Preferably, the cap and stem of the device define a substantially hollow device with an opening directed towards the bottom of the stem. In the preferred embodiment, a L-shaped lumen passes through the center of the stem and extends into the subdural space and out of the top of the cap of the device and through the patient's skin. The L-shaped lumen (a tube with a bore) allows the device to act as a fluid drain when it is connected to a drainage bag and the bag is located below the height of the subdural space. Gravity will thus allow for drainage. If the bag is filled with medication, however, and located above the height of the subdural space, then it will flow into the subdural space at least until the pressure on the inside (within the subdural space) equalizes with the pressure and weight of the fluid in the drainage bag. Alternatively, the subdural drain can be used with a hypodermic syringe aspirating fluid from the subdural space. In this procedure, the physician would poke the syringe either into the lumen or directly into the cap of the subdural drain. The syringe would either aspirate and withdraw excess fluid (or fluid withdrawn for analysis) or if the syringe were preloaded with medication the syringe would selectively inject the subdural space (through either the lumen or the hollowed toward the bottom of cap and stem) with medication.